Documentation: remove duplicated words

Remove many duplicated words under Documentation/ and do other small
cleanups.

Examples:
        "and and" --> "and"
        "in in" --> "in"
        "the the" --> "the"
        "the the" --> "to the"
        ...

Signed-off-by: Paolo Ornati <ornati@fastwebnet.it>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

Documentation/m68k/kernel-options.txt

@@ -415,7 +415,7 @@ switch to another mode once Linux has started.
 
   The first 3 parameters of this sub-option should be obvious: <xres>,
 <yres> and <depth> give the dimensions of the screen and the number of
-planes (depth). The depth is is the logarithm to base 2 of the number
+planes (depth). The depth is the logarithm to base 2 of the number
 of colors possible. (Or, the other way round: The number of colors is
 2^depth).